Is this tank freshwater? Shouldn't the jack and archer be in brackish? Cool fish BTW.
They are both in full FW. No problems at all thus far, in fact they are doing great.
does he fight with cichlids?
Not really, the odd disagreement from time to time, but nothing too serious. This could and more than likely will change as the jack gets bigger. But as they say if it 'aint broke, don't fix it.
To be honest, i think some fish are a lot like dogs to an extent. If you socialise them at a young age they will be much easier to deal with when they mature. I think people will have a lot more success mixing jacks with other fish if they are raised with other fish. Not to say that this always works.